Electrical signaling system



July 29, 1947. P.| c. coRNU 2,424,554

ELECTRICAL SIGNALING SYSTEM Filed March 1, 194s PCE A free/VFY Patented July 29, 1947 ELECTRICAL SIGNALING SYSTEM Pierre Lucien Charles Cornu, Paris, France, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application Marchl, 1943, Serial No. 477,648 In France August `23, 1939 7. Claims. (Cl. 177--311) provements in control, signaling and/or lsimilar One of the objects of this invention is to pron vide a system in which the energy required for the transmission of control or signaling is transmitted from the controlled station to the'control station and retransmitted either transformed or t not from the control station to the lcontrolled station in order to cause the desired control or signaling. l'

A further feature of this invention is presented in the fact that the energy required for the transmission of control or signaling is transmitted from the controlled station to the control station in the form of alternating current, transformed into continuous current at the control station and returned in this form to the controlled station in order to cause the desired control' or signaling.

A still further feature of the invention ispresented in the fact that the alternating current energy is transmitted fromthe controlled sta'- tion to the control station over twoA conductors of a line linking the two stations, transformed into continuous current atv the control station, and sent back to the controlled station over the two line conductors in order to effect the desired control or signaling.

A still further advantage of the invention resides in the fact that the energy transmitted from the controlled station to the control station is utilized during the interval between controlling or signaling `operations toeiect; acontinuous testing of the installation and signaling any trouble developingv and likely to affect Vits operation.

Another feature of the invention resides the .11

fact that the `polarity `of the continuous current applied-to the line conductors during the interval between controlling operations, to eiect Athe continuous testing of the l-ine and associatedl equipment, is reversed at the moment of-transmittin the control or the signalingcurrent.`

Still another feature of the 4invention is found in the arrangement in the control or signaling circuit of telephone circuits allowing establishi conductors Ll, L2.

2 control station and the controlled station, such communication being under no circumstances capable of producing interference with the con.- trol or signaling functions of the system.

These, as well as other objects and advantages of this invention will be apparent from the following detailed description of one embodiment thereof, which is not given in a limiting sense, but rather by way of example.

This invention resides substantially in the combination, construction, arrangement and relative location of parts, all as will be described in detail below.

In the accompanying drawing the single iigure comprises a schematic and diagrammatic illustration of the embodiment thereof selected for the purpose of disclosing the invention.

The control' station has been generally indicated by the reference numeral PCM and the controlled station'is generally indicated by the reference numeral PCE. 'I'he line comprising the conductors Ll and L2 extends between the two stations which may be separated any required distance as indicated by the broken line portions of these conductors. The signal and/or control current is supplied from any suitable =l alternating current source by the fused line ll,

l2 to the primary of the transformer TI. The secondary of this transformer is connected as shown through proper protection devices such as fuses to the controlled station end of the line These conductors extend to the control station and are connected to the primary of a transformer T2. The secondary of this transformer has its terminals connected across the input terminal of a suitable rectifier As those skilled in the art will appreciate, the rectifier may be of several acceptable forms. and may include as illustrated a plurality of rectifying devices connected in a bridge circuit as shown; A circuit for the signal lamps Lal and La2 is arranged as shown in conjunction with the switches l2, l5, 22 and 3|, as will be later described.

The positive terminal of the rectier Re is connected by a line to the movable contact of switch Y I3 which is also connected by a Wire to one terminal of the magnet I. The other terminal of this magnet is connected to one of the contacts of, a,switch Cm. The other terminal of this switch'is connected to the negative terminal of ment of telephone communication between .the l the rectifier and to the movable Contact of switch II. The signal or alarm circuit comprising the conductors AI and A2 includes the series switch I4 and the shunt switches 2| and 32. The back contact of switch I3 is connected to the magnet 2 which is grounded as shown. The back contact of switch is connected to the magnet 3, which in turn is connected to the mid-point of the primary of the transformer T2. This point is also `connected ,through a :condenser 7Co2 to the secondary of aitransformer t2 rforgcoupling the telephone equipment P2 to the line. The

other terminal of the secondary of transformer t2 is grounded as shown. k

The midpoint of the secondary of transformer TI is connected to the negative :terminal of sa rectifier TI whose positive terminal :isiconnected' Vmains energized the operator at the control sta- .tion issignaledthat the circuit is in good operat- 'ing condition.

to the magnet 4, which in turn -is groundedy atlits f l other terminal and `connected toone contact of the switch cmI. The negative {terminalxof :the rectier TI is connected to one terminal *.fof'a switch 4|, the other terminal of which is connected to one terminal of magnet 5, and to the positive terminal of a rectifier r2. This terminal iis=alsoiconnectedzto :the other rterminal Iof fswitch lcm1 :and `through .a .condenser ras :shown tto lground. :The negativeiterminal ofirectie'r'niis connected ithrough the :resistanceR'sto ground.

'Yllhe telephone :equipmentzPI isconn'ected cto ithe transformer tI ithe secondary :of which has one l'terminal Agrounded ,and ithe :other terminal rconznecte'd through .condenser .CozI to Jthemi'dpoint `of the secondary -.of transformer ifIlI ;As vvdiagrammatically aillustrated :in .fthe drawings, the lcontacts or switches controlled :by fthe :various imagnets are shown :in ivertical :alignment therewith. Thus the switches I5, 4:2, 4,343 and IrI are :operated :by .fthe magnet :I. .*Switches 22 and i.2e| are t operated iby :the :magnet 32. :Switches 333| :and 32garefoperatedlbyithe magnet 3. :Switch 4| is :operated rby :the .magnet 4. :Switch :5| :iS voperated :by magnet di .fand :controls fthe equip- ;ment CM or .a signal :associated therewith. The -diagrammatic illustration l:of thequipment QM :is ,provided to indicate that either ithe rcontrol thereof sor .ea lsignal in connection @therewith `,is .really :independent fof the :natur-,e of :the gequip- `gment., fas v.will ibe obvious to ,one 'skilled in Ithe fart. :The `various :magnets and switches controlled :thereby are represented Joy well Vknown electro- .magne'trelays ,of lwhich '.many practioal zforms :are available. V

The .foperation rof this system .will mow he sdefsoribed. When Sthe system iis :in use :theralter- :mating-"current source connected to :the conducftors .-Z'I and fl2 is supplying current to :the :net- ;work. This fcurrent `is .applied :to :the r.transmission `linerlJ'I and lL2 Ithroughthe l,transformer .'IYI and fffrom the line through -the :transformer across `the rinput terminals of the frectier Re. This condition exists throughout normal -operationof the system. As -a vresult 1of ythis a -circuit will be completed to fthe relay magnets i2 and .4 as follows: from ground through imagnet 'the movable -nger of lswitch I3 -and -the aback contact normally Aengaging iit to the positive termie nal of rectifier Re, from the negative terminal of this rectier through `the movable contactv of switch II and its back contact, magnet 43,-mid point of Athe-primary of transformer T2 overfthe conductors LI Yand L2 in `parallel to the midpoint of the secondary of transformer 'TI and `from thereto vand through the rectier TI, and the I If `vit be :assumed 'that an open circuit on the Vilineazomprising:the conductors LI and L2 occurs, :itifollows thatthe-circuit for magnet 2 is opened, with the result that switch 22 rst opens and .-switch 2| vvwhich .was open closes. Signal lamp LzJI .is extinguished, indicating trouble on the line. The closing of switch 2| completes the alarm -circuit AI-A2 setting a suitable alarm, not shown, in operation, further signaling to the .operator thatrsomething tis wrong withsthe fline. :21h zthe lerent .that f the ground connection .at f'tlrerstation joriboth of themrdeveloped a very ,high resistant -condition the'same result, namely .the :extinguishing of :light Lal and rthe tenergiza- .tienmf ,the alarm will follow, indicating that the system is not toperating properly.

Should eitherzor-both'ofthe line conductors LI -or 1;2becomelfgrounded, magnetl4 becomes shorteircuited :in .fan -obvious manner, Awith vthe result rthatmagnet 3 -is energized to operate switches -,3| and .32. Theoperationfoifswitch 3| Aopensfthe mirouit for v:lamp LaIysextinguishing it. The ,op- (eration iof switch,3.2 willfcomplete the alarm :cir-

cuit AI-A2 giving a further signal of trouble son the Aline;

-In itheevent that'energy `eitherfceases fto be itransmitted from 'the controlled v'station yPCE 4to :the rcontrplfstation PCM, or ceases fior any reason'to fheyfreceived -at PCM, ,the supplygof energy ,forjhe relay ,2 will be cut off -so fthatfas before, .lampiLwI `will;beextinguished:andthe-alarm cir.- .cuit will goe completed. Thus `fit -.wil1;be seen that so long as the signal by supervisory lamp-Lal `,is energized the circuit `#is in operating condition, :hutasfsooniasfit is :extinguished -from :any 'oneof .the useveral fpossible reasons :explained above, #hubieron the :line zwill :be indicated.

, ,ln order -to -cause transmission tof a control signal tofthe controlled station the `switchqCm [is -closed, -completing a :circuit for the magnet I ,which is held ,ras long .as fthis Yswitch vis closed. This circuit is obvious from .the fdrawing. VThe energization A,of magnet I lclosesswitches ,I5 and .ltgopensiswitch I4, shiftsqthe :positive side of the rectiiierRezto .the -front contact of switch 7|"3,-and shitsrthenegative.'connectionof the rectifier fto the )front contact fof switch tI'I. The Vclosing :of switches |52 :and I5 during :this period :maintains the circuit vffor fthe supervisory lamp Lal. The opening of switch I4 breaks the signal alarm circuitiuringithisfperiod. The operation of :switches {Ill :and EI 3connects ithe rectifier fR-.e in circuit with them andground as will fbe readily seen ifrom the #drawings At Athis time 'magnet I"4 Iis =not yeffectively-energizedfand switch 4'I isfclosed. The shifting of switch I'Sbreaks the'circuit for magnet 2 s o that -switch 22 `opens and switch 2-I closes. The :circuit #for magnet '3 upon Ithe `closing f ol" switch 4| is 1 completed lthrough switch 4-I magnet 5, rectierr? "and'resistance iR to ground Magnet "5 Vremains energized but Amagnet l3 does not remain energized owing to the high value of resistance R in series with the resistance of magnet 5.

The energization of magnet 5 closes switch 5|, causing the equipment CM to undergo the desired control, or causing the operation of the signal device associated therewith. When the signaling operation has been eiectively completed switch cmi is .closed by the operation of the control or signal apparatus, so that rectifier r2 and resistance R are .short-circuited. As a result the current for the magnet 3 is strong enough to energize the magnet so as to close switch 32 and operate switch 3|. The closing of switch 32 does not complete the alarm circuit because switch I4 is open. However, the operation of switch 3| causes the signal lamp La2 to be energized through closed switch- I5, the front contact of switch 3|, and closed switch l2, indicating at the control station that the control signalhas been properly `transmitted and the desired control or signaling at the controlled station has been effected. Upon the opening of switch Cm at the completion of this operation, the control circuit is broken and the parts returned to the normal position shown in the drawings, at which time, of course, the alarm circuit is open at switch 2| and the supervisory lamp Lal is operated.

Telephone communication can be effected over the circuit from either station P| and P2'. The secondary of transformer t2 is grounded at one terminal and its other terminal is connected through the capacitor Co2 to the primary of transformer T2, over the line conductors LI-L2 in parallel to the midpoint of the secondary of transformer TI, and thence through the capacitor Col and the secondary of transformer tl to ground. Thus the telephone circuit is ready for operation at all times without interference with the other functions of the circuits.

From the above description it will be seen that the subject matter of this invention can be applied in various physical forms without departure from the novelty thereof. For example, those skilled in the art will appreciate that capacitive coupling devices could be employed in place of the transformers without aiecting the basic operation of the system. I do not, therefore, desire to be strictly limited to the disclosure as given herein for illustrative purposes, but rather by the scope of the appended claims.

What is claimed is:

1. In a control and signal system a controlled station, a control station, a circuit comprising two line wires connecting the stations, means at the controlled station applying an alternating current to said circuit for transmission to the control station, means at the control station for rectifying said current and applying it with a given polarity to a second circuit between the stations comprising the line wires in multiple and the ground, means at the control station for reversing the polarity of application of the rectified current to said second circuit, and means at the controlled station responsive to such reversal for accomplishing a desired control.

2. In a control and signal system a controlled station, a control station, a circuit comprising two line wires connecting the stations, means at the controlled station applying an alternating current to said circuit for transmission to the control station, means at the control station for rectifying said current and applying it with a given polarity to a second circuit between the stations comprising the line wires in i'nultiple and the ground, means at the control 'station for reversing the polarity of application of the rectiiied current to said second circuit, means *at the controlled' station responsiveto such reversal for accomplishing a desired controlfmeans responsive to said accomplished control tocause a variation 'of said reversed current, and means at the control station responsive to said variation of current for indicatingthe accomplishment of said control.V

3.`In a control and signal systemja controlled station, a control station,` a circuit comprising two line` wires connecting the stations, meansat the controlled station applying an alternating current to said ,circuit for transmission to the Hcontrol station, means at thev control station for rectifying saidv current Aand applying itjwith a given polarity to a circuit between thestatiOns comprising theline wires in multiple and the ground, means in said iirst circuit at the control station for indicating a variation of the current flowing in said circuits, means in the second circuit for controlling the connection of the indicating means in circuit and thereby supervising the first and second circuits and the alternating current applying means, means at the control station for reversing the polarity of application of the rectiiied current to said secondvcircuit, means at the controlled station responsive to such reversal for accomplishing a desired control, means responsive to said accomplished control to cause a variation of said reversed current, and means at the control station responsive to said variation of current for indicating the accompiishment of said control.

4. In a control and signal system a controlled station, a control station, a circuit comprising two line wires connecting the stations, means at the controlled station applying an alternating current to said circuit for transmission to the control station, means at the control station for rectifying said current and applying it with a given polarity to a circuit between the stations comprising the line wires in multiple and the ground, means in said rst circuit at the control station for indicating a variation of the current flowing in said circuits, means in the second circuit for controlling the connection of the indicating means in circuit and to thereby supervise the first and second circuits and the alternating current applying means, means at the control station for reversing the polarity of application of the rectified current to said second circuit, means at the controlled station responsive to such reversal for accomplishing a desired control, means responsive to said accomplished control to cause a variation of said reversed current, a second indicating means in the first circuit, and means responsive to said variation of current for controlling the connection of the second indicating means and thereby indicate the accomplishment of said control. v

5. In a system of the type described including a control station and a controlled station, the combination including a pair of conductors extending between the control station and the controlled station, means at the controlled station end for generating alternatingV current and connected with both conductors as a complete circuit to transmit the current to the control station end of the conductors, a rectifier connected to the parallel conductors at the control station to transmit direct current to the controlled station, a grounded direct current circuit between the control station and the controlled station 1.connerfted with the output terminals of said :rectifier 'including .said conductors in :parallel, a super-yisory circuit .at the -controlled vstation, Jneans `for opening :and #closing lsaid :supervisor-y ,circuit, and :means fat the 'control Ystation ;5

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,719,471 Hoffman July 2, 1929 2,037,565 Dozler Apr. 14, 1936 2,039,405 Green May 5, 1936 1,740,485 Wensley Dec. 24, 1929 1,765,475 White June 24, 1930 1,142,252 Harkness June 8, 1915 1,754,239 Niles Apr. 15, 1930 2,318,364 Bostwick May 4, 1943 FOREIGN PATENTS Number Country Date 191,697 Switzerland Sept. 16, 1937 

